Heat-shrinkable thermoplastics are known to be useful as flexible packaging materials for vacuum packaging various foodstuffs, including meat. Such plastic materials, however, while generally suitable for packaging meat, understandably have difficulties in successfully packaging sharp or bony products. For example, attempts to package bone-in primal cuts of meat usually result in an unsatisfactorily large number of bag failures due to bone punctures. The use of cushioning materials such as paper, paper laminates, wax impregnated cloth, and various types of plastic inserts have proved to be less than totally satisfactory in solving the problem. The preparation of special cuts of meat or close bone trim with removal of protruding bones has also been attempted. However, this is at best only a limited solution to the problem since it does not offer the positive protection necessary for a wide variety of commercial bone-in types of meat. Furthermore, removal of the bone is a relatively expensive and time-consuming procedure.
The use of heat-shrinkable bags having one or two heat-shrinkable patches adhered thereto has recently become a commercially-preferred manner of packaging a number of bone-in meat products. However, even the bags having two patches thereon leave "uncovered regions" (i.e., regions of the bag which are not covered by the patch, also herein referred to as "bald regions") which are more vulnerable to puncture because they do not have a patch adhered thereover.
Patch bags used in packaging bone-in meat products are generally provided in a "lay-flat" position, in which the factory seal or seals are in contact with a table surface on which the patch bag is placed during insertion of the meat product into the bag. However, it has been found that for certain cuts of meat, the uncovered regions along one or more edges of the bag are likely to be contacted with exposed bone at the periphery of the meat product which is being inserted into the bag. As a result, some packagers of such cuts have been "rotating" the bag about ninety degrees before inserting the bone-in meat product into the bag. In this manner, the uncovered region of the bag is positioned some distance away from the exposed bones along the periphery of the meat product.
In response to this problem, a patch bag which has come to be known as a "rotated patch bag" has been developed, in which the patches cover at least a portion of an edge of the bag, these bags having uncovered regions between the patches, these regions being positioned away from the bag edges. However, in the process of making such patch bags, it has been found that the creases (in the tubing from which the bag portion is made) interfere with the beat sealing. More particularly, some of the seals have a "line" therethrough. This line is believed to be associated with an imperfect seal which either leaks or is a particularly weak spot in the seal. It would be desirable to produce a patch bag having patches which cover one or more bag edges and which has seals which are not made across creases in the bag film.